Impact of Photovoltaic Power Plant on the Transient Stability Compared With Synchronous Generator

Abstract: In the recent years the power system is changing and distributed generation (DG) units are used in power systems at the distribution level regularly. The power demand is increasing and it can be fulfilled by use of renewable energy sources like solar energy. This paper discusses the using of Photovoltaic power plant as a DG in distrusted network and its effect on transient stability. In order to scrutinizing the effect of PV system as a DG in redial distribution system, 3 IEEE standard test systems are simulated with Dig SILENT software. In all 3 networks a short circuit fault is taken and the effect of that is analyzed in 2 modes; first with synchronous generators (SG) and second with Photovoltaic (PV) power plant and the results are compared. Comparing the results shows that in all 3 networks PV power plant work could save the stability in active power and voltage without using any extra devices

Frosted branch angiitis caused by Varicella Zoster virus in an immunocompetent patient

Introduction: Frosted branch angiitis(FBA) is a panuveitis with sheating of all retinal vesssels. Case presentation: Herein we report an immunocompetent person who presented with fever, headache, atypical rash, and hazy vision. Ophthalmoscopy of both eyes revealed perivascular sheathing with frosted branch angiitis pattern in veins, patchy retinal hemorrhages. Aqueous PCR analysis turned positive for VZV. Discussion: This case illustrates that VZV should be considered in the differential diagnosis of retinal perivasculitis. Since a rapid and accurate diagnosis is crucial for prompt administration of antiviral therapy, PCR-based analysis of aqueous humor is a valuable tool for detecting viruses. © 2015, IRAN. J. MICROBIOL. All rights reserved

Comparison of efficacy and ocular surface toxicity of topical preservative-free methylprednisolone and preserved prednisolone in the treatment of acute anterior uveitis

PURPOSE:: The aim of this study was to compare the antiinflammatory effect and ocular surface toxicity of topical nonpreserved methylprednisolone sodium succinate 1 and preserved prednisolone acetate suspension 1 for the management of acute anterior uveitis (AAU). METHODS:: In this prospective, randomized, investigator-masked, comparative clinical trial, patients with mild-to-moderate noninfectious AAU were assigned randomly to receive either hourly nonpreserved methylprednisolone 1 (group A) or preserved prednisolone 1 (group B) eye drops followed by a 2-week tapering regimen. Anterior chamber cells and flare were clinically evaluated for the objective comparison of the antiinflammatory effect. The main outcome measure was the percentage of patients with a resolution of inflammation (anterior chamber cells <1+) on day 14. Ocular surface toxicity was assessed by means of the corneal fluorescein staining score, tear breakup time, Schirmer I test, and questionnaire-based grading of ocular discomfort parameters. RESULTS:: Seventy-two eyes of 68 patients were studied, of which 38 eyes were enrolled in group A and 34 eyes were enrolled in group B. On day 14, 76.3 of the patients in group A had resolution of inflammation compared with 70.6 of the patients in group B, proving noninferiority (� = 0.303, P = 0.582). The mean anterior chamber cell grade reduction for patients in group A was similar to that in group B (2.52 vs. 2.86, respectively; P = 0.92). Group A patients showed significantly lower corneal fluorescein staining scores (P < 0.001) and reported milder subjective ocular discomfort (0.55 vs. 1.43, P = 0.01) as compared with group B. CONCLUSIONS:: Both preparations demonstrated equal antiinflammatory effects for the treatment of AAU. Nonpreserved methylprednisolone eye drops exhibited a significantly lower ocular surface toxicity profile and milder subjective discomfort when compared with that exhibited by preserved prednisolone. Copyright © 2014 by Lippincott Williams & Wilkins

Chronic subclinical inflammation after phakic intraocular lenses implantation: Comparison between Artisan and Artiflex models

Purpose To compare chronic subclinical inflammation induced after implantation of Artisan vs. Artiflex phakic intraocular lenses (pIOLs). Methods This prospective, comparative, non-randomized study included consecutive patients with moderate to high myopia who underwent Artisan or Artiflex pIOL implantation with standard surgery and postoperative care. Anterior chamber flare was assessed quantitatively using laser flare photometry (LFP) at baseline, 1 week, 1 month, 3 months, 6 months, and 2 years after surgery. Results PIOLs were implanted in 72 eyes (40 patients); Artisan pIOLs in 16 eyes (Artisan group) and Artiflex pIOLs in 56 eyes (Artiflex group). The mean preoperative anterior chamber flare was 6.5 ± 2.3 (range, 4.2�9.5) photons per millisecond (ph/ms) and 4.2 ± 0.9 (range, 2.5�11.7) ph/ms in Artisan and Artiflex groups, respectively (P = 0.400). In spite of early postoperative rise, the flare value returned to preoperative levels 6 months after pIOL implantation and remained stable up to 2 years. The amount of flare was not statistically different between Artisan and Artiflex groups in any postoperative follow-up (all P > 0.05). The trend in flare changes was not different between the studied groups (ANCOVA, P = 0.815). Conclusion The inflammatory response induced by implantation of either type of Artisan and Artiflex pIOLs is short-lived without statistically significant difference between the two models. © 2017 Iranian Society of Ophthalmolog

Update on Bartonella neuroretinitis

Purpose: To review the clinical features, diagnosis, treatment modalities, and prognosis of Bartonella-associated neuroretinitis. Methods: This is a narrative review on Bartonella-associated neuroretinitis including general and ophthalmological aspects of the disease. A comprehensive literature review between January 1950 and September 2018 was conducted in PubMed database. Epidemiology, clinical features, diagnosis, treatment, and prognosis of Bartonella neuroretinitis were reviewed. Results: Cat scratch disease (CSD) is a worldwide distributed systemic infectious disease caused by a bacterium, Bartonella henselae (B. henselae) which is usually transmitted to humans through contact with infected cats. Ocular manifestations of CSD are diverse, with neuroretinitis and superficial retinal infiltrates being the most common and typical manifestations. Neuroretinitis typically presents as optic disc edema with a partial or complete macular star in association with mild vitritis. Macular star may be absent at the initial presentation, becoming evident 1�2 weeks after the onset of optic disc edema. Diagnosis of CSD is confirmed by reliable laboratory tests. Neuroretinitis usually has a self-limited course. Antibiotic therapy is required for severe systemic disease and vision-threatening ocular involvement. The adjunctive use of oral corticosteroids may further improve the visual outcome. Conclusions: The diagnosis of Bartonella-associated neuroretinitis is based on typical clinical findings and positive serology. The prognosis is usually favorable in immunocompetent individuals. © 2019 Iranian Society of Ophthalmolog

Catching the therapeutic window of opportunity in early initial-onset Vogt�Koyanagi�Harada uveitis can cure the disease

Purpose: Vogt�Koyanagi�Harada (VKH) disease is a primary autoimmune granulomatous choroiditis that begins in the choroidal stroma. The aim of this review was to gather a body of evidence for the concept of a window of therapeutic opportunity, defined as a time interval following initial-onset disease during which adequate treatment will substantially modify the disease outcome and possibly even lead to cure, similar to what has been described for rheumatoid arthritis. Methods: We reviewed the literature and consulted leading experts in VKH disease to determine the consensus for the notion of a therapeutic window of opportunity in VKH disease. Results: We found a substantial body of evidence in the literature that a therapeutic window of opportunity exists for initial-onset acute uveitis associated with VKH disease. The disease outcome can be substantially improved if dual systemic steroidal and non-steroidal immunosuppressants are given within 2�3 weeks of the onset of initial VKH disease, avoiding evolution to chronic disease and development of �sunset glow fundus.� Several studies additionally report series in which the disease could be cured, using such an approach. Conclusions: There is substantial evidence for a therapeutic window of opportunity in initial-onset acute VKH disease. Timely and adequate treatment led to substantial improvement of disease outcome and prevented chronic evolution and �sunset glow fundus,� and very early treatment led to the cure after discontinuation of therapy in several series, likely due to the fact that the choroid is the sole origin of inflammation in VKH disease. © 2018 The Author(s